Idiopathic cervical dystonia (CD) and benign essential blepharospasm (BEB) are the most common forms of focal dystonia. Previous autopsy and imaging studies suggested that these disorders are not accompanied by structural brain abnormalities. However, recent brain voxel-based morphometry (VBM) studies of these conditions suggest that there actually may be changes in gray matter. The objective of this stdy was to detect possible gray matter abnormalities in patients with CD and BEB using VBM and to compare the results between the two conditions and with age- and gender-matched controls. High-resolution MRI was employed to evaluate healthy controls and individuals with BEB and CD. Eleven BEB, 9 CD, and 14 healthy control subjects were imaged. VBM revealed alterations of gray matter structures involved in sensorimotor processing in the individuals with focal dystonia. In CD subjects there was increased gray matter in the thalamus, caudate head bilaterally, superior temporal lobe, and left cerebellum, while gray matter was decreased in the putamen bilaterally. BEB subjects had increased gray matter in the caudate head and cerebellum bilaterally as well as decrease in the putamen and thalamus bilaterally. These findings strongly underline the recent notion that idiopathic focal dystonias might have a detectable structural correlate. They also demonstrate structural similarities of the investigated focal dystonias, possibly reflecting a shared common pathophysiological origin.

In both, BSP and CD, increased basal-ganglia activation could be demonstrated in a task not primarily involving the dystonic musculature affected by these disorders. Comparable activation changes may also indicate a common pathway in the pathophysiology in BSP and CD.

Dopaminergic dysfunction is thought to play a pivotal role in human immunodeficiency virus (HIV)-related dementia. Decreased dopamine (DA) levels in the cerebrospinal fluid (CSF) and neuronal loss in the substantia nigra (SN) have been reported in HIV-infected patients, suggesting nigrostriatal damage. Structural changes detectable as hyperechogenicity in transcranial ultrasound (TCS) scans of the SN have been reported in patients with Parkinson's disease (PD) and other neurological conditions. In this study, we assessed the echomorphology of the SN in 40 HIV-positive patients compared to 40 age- and sex-matched healthy controls and correlated these findings with CSF levels of DA and the metabolites homovanillic acid (HVA) and 3,4-dihydroxy phenylacetic acid (DOPAC) and with neuropsychologic performance. We observed that the SN of HIV-infected patients was hyperechogenic relative to that of controls (0.07 +/- 0.05 vs. 0.04 +/- 0.07 cm(2); mean +/- SEM; P < 0.001) and that this SN hyperechogenicity was correlated with decreased DA levels in the CSF, decreased CD4 cell count, and an impaired performance in the psychopathology assessment scale (AMDP) subtest for drive and psychomobility. An association to CDC stage, duration of HIV infection, or presence of HIV dementia was not observed. Our results indicate changes in the nigrostriatal system in HIV-infected patients that are detectable as hyperechogenic SN precede prominent extrapyramidal symptoms and cognitive dysfunction.

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